ntfs: fix FITRIM range alignment
ntfs_trim_fs() aligns the start of a free extent up to the device discard
granularity, but derives the discard length by aligning the original extent
length down. When the free extent start is not discard-aligned, adding that
length to the aligned start can extend the discard past the free extent and
into allocated clusters.
For example, with 4 KiB clusters and 32 KiB discard granularity, the free
extent [4 KiB, 36 KiB) becomes the discard range [32 KiB, 64 KiB), so
28 KiB beyond the free extent may be discarded.
Align the absolute end of the free extent down and derive the length from
the two aligned endpoints. Skip extents that contain no full discard unit.
Reproduced with a 4 KiB-cluster NTFS filesystem on scsi_debug configured
for 32 KiB discard granularity and read-zero-after-trim. Before this
change, FITRIM zeroed seven allocated 4 KiB clusters following an unaligned
32 KiB hole. With this change, the same data remains intact across FITRIM
and remount.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
No advisories yet.
Wed, 28 Oct 2026 10:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ntfs: fix FITRIM range alignment ntfs_trim_fs() aligns the start of a free extent up to the device discard granularity, but derives the discard length by aligning the original extent length down. When the free extent start is not discard-aligned, adding that length to the aligned start can extend the discard past the free extent and into allocated clusters. For example, with 4 KiB clusters and 32 KiB discard granularity, the free extent [4 KiB, 36 KiB) becomes the discard range [32 KiB, 64 KiB), so 28 KiB beyond the free extent may be discarded. Align the absolute end of the free extent down and derive the length from the two aligned endpoints. Skip extents that contain no full discard unit. Reproduced with a 4 KiB-cluster NTFS filesystem on scsi_debug configured for 32 KiB discard granularity and read-zero-after-trim. Before this change, FITRIM zeroed seven allocated 4 KiB clusters following an unaligned 32 KiB hole. With this change, the same data remains intact across FITRIM and remount. | |
| Title | ntfs: fix FITRIM range alignment | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-28T10:34:26.772Z
Reserved: 2026-09-25T10:25:14.391Z
Link: CVE-2026-99108
Vulnrichment
No data.
NVD
No data.
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.